Ionis Pharmaceuticals, Inc. announced that the U.S. Food and Drug Administration (FDA) has accepted for Priority Review the New Drug Application (NDA) for olezarsen, an investigational RNA-targeted medicine for the treatment of adults with familial chylomicronemia syndrome (FCS). The FDA has set an action date of December 19, 2024 and indicated they are not currently planning an advisory committee meeting for olezarsen. Priority Review is a designation for medicines that have the potential to provide significant improvements in the treatment, prevention or diagnosis of a serious disease, with the expectation of the FDA taking action within six months, compared to 10 months under standard review.

The application to the FDA was based on positive results from Balance, a global, multicenter, randomized, double-blind, placebo-controlled Phase 3 study. The study results were presented at the 2024 American College of Cardiology (ACC) Annual Meeting and published simultaneously in The New England Journal of Medicine (NEJM). The U.S. FDA granted olezarsen Fast Track designation for the treatment of FCS in January 2023, as well as Orphan Drug designation and Breakthrough Therapy designation in February 2024.

Ionis is planning additional regulatory filings for the treatment of FCS in the European Union this year. In addition to FCS, Ionis is evaluating olezarsen for the treatment of severe hypertriglyceridemia (sHTG) in three Phase 3 clinical trials ? CORE, CORE2 and ESSENCE, all three of which completed enrollment in the first half of 2024.

CORE and CORE2 enrolled more than 1,000 sHTG patients with fasting triglyceride levels =500 mg/dL; ESSENCE enrolled more than 1,400 high triglyceride patients with fasting triglyceride levels =150 mg/dL to <500 mg/dL who were diagnosed and/or at risk for atherosclerotic cardiovascular disease as well as patients with fasting triglycerides =500 mg/dL. sHTG is a common, life-threatening condition that can result in severe health complications, including potentially fatal acute pancreatitis (AP). Data are expected in the second half of 2025.